USS Puritan was originally designed as a double-turreted ironclad monitor, the plans were altered to the specifications of John Ericsson, Puritan’s builder, following a long debate with the Navy; she was built with a single turret. Contracted 28 July 1862 to Ericsson, who in turn subcontracted the hull to the Continental Iron Works of Greenpoint, New York and the machinery to the Allaire Iron Works of New York City, she was launched 2 July 1864. However, due to delays in construction and the casting of the 20-inch smoothbores she was never completed, her construction being suspended in 1865.